Method for the manufacture of motor vehicle body parts

ABSTRACT

A method for the manufacture of motor vehicle body parts is disclose. The method includes providing blanks of flat material, deep-drawing of a first deep-drawing contour on the blanks by means of a first forming tool, and deep-drawing of a second deep-drawing contour by means of a second forming tool.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to German Patent Application No. 102013011951.0 filed Jul. 18, 2013, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The technical field relates to a motor vehicle body structure, and more particularly to a method for the manufacture of motor vehicle body parts, in particular by the deep-drawing of blanks of flat material.

BACKGROUND

Deep-drawing methods are generally known in motor vehicle manufacture. For the deep-drawing of blanks of sheet metal, generally forming tools are used having at least two parts, designated as a punch and a die, wherein the die generally has a recess into which the blank is pressed by the punch during the deep-drawing. The shape of the finished deep-drawn part is predetermined by the shapes of the punch and die. When body parts for different vehicle models with different dimensions are required, generally an appropriate forming tool must be provided for each variant of such a deep-drawn part, which involves considerable costs.

In order to be able to manufacture different body models efficiently and economically, it would be desirable in principle to only make particular body parts model-specific and to combine these with other components which are comprehensively identical over the models. If, however, such a standard component has to be combined with different types of model-specific body parts, then all these model-specific types of body parts must have a suitable interface for the mounting of the component which is comprehensively identical over the models. In order to form this interface, the tools used for the deep-drawing of these body parts must be precisely congruent locally, which in turn increases the expenditure in the manufacture of the tools.

SUMMARY

It is an object of an embodiment of the present disclosure to provide a method for the manufacture of motor vehicle body parts, by which variants of a given body part can be provided simply and economically for different vehicle models. The problem is solved by a method for the manufacture of motor vehicle body parts in accordance with the following process: (a) provision of blanks of flat material; (b) deep-drawing of a first deep-drawing contour on the blanks, by means of a first forming tool, in order to obtain semi-finished parts; (c) deep-drawing of a second deep-drawing contour on the semi-finished parts by means of a second forming tool. The method enables the economically priced manufacture of numerous variants of a motor vehicle body part in different ways.

A first way is to select the first or the second forming tool from a set of several forming tool. Thus, if for example a set of n first forming tools and a set of m second forming tools is available (wherein at least one of these sets contains more than one tool), by means of a total of n +m tools up to n x m variants of the body part can be obtained. Even if one of the sets contains only one single tool, a cost saving is able to be realized, because the forming tools respectively only form one part of the body part and therefore generally can be formed smaller, but in any case more simply, than a tool with which the entire body part is formed.

Generally, the model-specific body parts will differ from one vehicle model to the other in at least one dimension. It is therefore expedient if in step (a) blanks with different values of a dimension are provided for these different vehicle models and the selection of the first or of the second forming tool to carry out step (b) and/or (c) takes place by means of the value of the dimension.

A second way, for the placing of the first and second forming tool to carry out the deep-drawing step (b) or (c) includes determining respectively different reference points on the blank. When the position of at least one of the reference points is different depending on the variant of the body part which is to be manufactured, different positions of the deep-drawing contours result in a variant-specific manner. In extreme cases, any desired multiplicity of variants of a motor vehicle body part can thus be manufactured with only two tools, in which these are positioned differently on the blank.

When blanks are provided with different values of a dimension according to the variant, the distance between the reference points is preferably different according to the value of the dimension. Typically, the dimension in question is a longitudinal dimension of the blank.

The first and the second deep-drawing contour are preferably formed on marginal areas of each flat material blank which are separated from one another. Thus, both deep-drawing steps can take place simultaneously, or respectively, if the first takes place before the second deep-drawing step, it is ensured that the shape of the region of the blank which is formed by the second tool is always identical independently of the first deep-drawing step which has been carried out previously. In particular, the first and the second deep-drawing contour can be formed on opposite longitudinal edges of the blank. This is expedient in particular in the case of a body part which is to be installed in a longitudinal beam of a motor vehicle body.

Alternatively, the first and the second deep-drawing contours can also be formed on opposite head ends of the blank. A central section of the blank connecting these head ends can be reinforced before or after the deep-drawing by roll-forming This variant is expedient in particular for transverse beams of motor vehicle bodies, which can have different lengths in a model-specific manner and are connected at their head ends with other body parts, in particular longitudinal beams.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and:

FIG. 1 shows a lateral view, which illustrates the placing of parts of a substructure in a vehicle;

FIG. 2 shows a perspective view of the substructure, halved along the longitudinal central plane of the vehicle;

FIG. 3 shows the longitudinal beam of the substructure of FIG. 2;

FIG. 4 shows the longitudinal beam, pulled apart into an upper shell and a lower assembly;

FIG. 5 shows the lower assembly of the longitudinal beam, viewed from a different perspective;

FIG. 6 shows a pulled-apart illustration of components of the lower assembly;

FIG. 7 shows a section along the plane VII-VII of FIG. 3;

FIG. 8 shows a deep-drawn part of the upper shell;

FIGS. 9 a-d show steps in the manufacture of one of the wall parts shown in FIG. 6;

FIGS. 10 a-d show steps of an alternative manufacturing method; and

FIGS. 11 a-b show steps of a manufacturing method for a transverse beam.

DETAILED DESCRIPTION

The following detailed description is merely exemplary in nature and is not intended to limit the present disclosure or the application and uses of the present disclosure. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description.

FIG. 1 shows a lateral view of a motor vehicle. A substructure concealed in the interior of the vehicle includes two longitudinal beams, which run in mirror image to one another along the right and left flank of the vehicle, and the course of which is illustrated in FIG. 1 by dashed lines in a rear part of the vehicle. The longitudinal beams extend over the entire length of the vehicle, from a front bumper to a rear bumper. The manufacturing method explained below is in fact able to be applied basically to any desired parts of the longitudinal beams and other body components, however the course of the longitudinal beams is illustrated only in the rear part of the vehicle, because the following example embodiments are limited to this area.

The part of one of the longitudinal beams, shown in FIG. 1, is divided into a rear longitudinal beam section 1, a transition section 7 and a central longitudinal beam section 9. The rear longitudinal beam section 1 extends from a rear bumper 2 substantially horizontally towards the front. On the other side of a rear wheel axis 3, the transition section 7 adjoins, which extends to below rear seats 4 in a passenger compartment 5 of the vehicle, and the upper side of which extends that of the rear bumper section 1 horizontally towards the front. The underside of the transition section 7 is sloping towards the front, in order to form a connection to the central longitudinal beam section 9, which extends under the passenger compartment 5 towards the front. On a front edge of the transition section 7, a heel plate 6 is mounted beneath a front edge of the seats 4.

FIG. 2 shows in a perspective view a rear region of the substructure of the body of the vehicle of FIG. 1. The view shows a portion of the right-hand longitudinal beam, with respect to the direction of travel, with the sections 1, 7 and, respectively halved along the longitudinal central plane, three transverse beams 10, 11, 12 connecting the longitudinal beams with one another. The transverse beams 10, 11, 12 are joined together respectively from two metal sheets which are welded to one another along their edges. In the case of the foremost transverse beam 12, one of these sheets is the heel plate 6. A roll-formed profile 13 is joined onto the rear side of the heel plate 6 and is welded therewith to a hollow profile with a closed cross-section. The right-hand end of the transverse beam 12 is covered by an extension 14 of the transition section 7. Beneath the extension 14, a connection 15 can be seen for the central longitudinal beam section 9 which is not shown in FIG. 2.

The central transverse beam 11 is composed of two roll-formed profiles 16, 17 with a respectively hat-shaped cross-section, which are welded to one another along their longitudinal edges. The rear transverse beam 10 is also composed of two roll-formed profiles, which form here a cross-section which is open towards the rear. The latter is only supplemented in a later stage of manufacture by a body sheet to a hollow profile.

FIG. 3 shows the rear longitudinal beam section 1 without the transverse beams 10, 11, 12, in order to enable a differentiation between these and the extensions of the rear longitudinal beam section 1 provided for their fastening. Two extensions 18, 19 are associated here with the central transverse beam 11, which extensions have respectively at their distal end a hat-shaped cross-section complementary to the roll-formed profiles 16, 17, and which are welded both to one another and also to an inner flank 21, an upper side 22 and an underside of the longitudinal beam section 1 not visible in the figure.

FIG. 4 shows the rear longitudinal beam section 1 of FIG. 3 in a partially pulled-apart view, separated into an upper shell 23 and an assembly 24. The upper shell 23 includes a deep-drawn front section 25, which is to be assigned to the transition section 7 of the longitudinal beam, and a roll-formed rear section 26, which belongs to the rear longitudinal beam section 1. The sections 25, 26 are welded with one another at the height of the extension 18, wherein the flanges, overlapping one another and welded, of the front and of the rear section 25, 26 are largely covered by the extension 18. The assembly 24 also includes a roll-formed rear section 27 as part of the rear longitudinal beam section 1, and a channel-shaped deep-drawn front section 28 as part of the transition section 7, which are welded with one another, approximately adjacent to the extension 19, to a lower shell 20.

The distance, increasing towards the front, between the sections 25, 28 is filled by two deep-drawn wall parts 29, 30 of the assembly 24. The wall parts 29, 30 have at their front edge respectively an approximately rectangular cutout 31, which is shaped in order to receive the roll-formed profile 13 of the transverse beam 12. As the extension 14 covers the lateral end of the heel plate 6, the transverse beam 12 must be placed and fastened between the upper shell 23 and the assembly 24, before both are joined together and are welded along flanges 32, 33 of the roll-formed rear sections 26, 27 or respectively 34, 35 of the front section 25 and of the wall parts 29, 30. Thereby, the distance between the longitudinal beams is established before the mounting of the transverse beams 10, 11.

The extensions 18, 19 for fastening the central transverse beam 11 project to different extents towards the center of the vehicle, so that the central transverse beam 11, after the connecting of the upper shell 23 with the assembly 24, can be placed from above onto the extensions 18, 19 and can be welded therewith.

FIG. 5 shows the assembly 24 from a different perspective, viewed from the outside of the vehicle. The joint between the roll-formed rear section 27 and the wall parts 29, 30 can be clearly seen here, and also several components joined laterally onto the outer wall part 30 or the front section 28, in particular a substantially horizontal plate 37 with receiving holes 38, a likewise substantially horizontal adapter plate 39, which carries a fastening element 40 for a guide of the axis 3 (a second fastening element 41 is provided in the deep-drawn front section 28) and a substantially vertical plate 42, which bridges the difference in height between the plate 37 and the adapter plate 39 and reinforces the latter, in which it is welded to both.

FIG. 6 shows the assembly 24 in a pulled-apart representation. It can be seen here that the front section 28 has a substantially U-shaped cross-section with two lateral wings 43 and a base wall 44 connecting the wings 43, and that the wall parts 29, 30 have respectively an upright wall surface 45, from the upper edge of which the flanges 35 are angled in respectively opposite directions, whereas at the lower edge of the wall surfaces 45 angled flanges 36 run towards one another.

FIG. 7 shows a cross-section through the transition section 7 of the longitudinal beam along the plane designated by VII-VII in FIG. 3. The flanges 35, running apart, at the upper edges of the wall surfaces 45 are welded to the front section 25 of the upper shell 23; the flanges 36, running towards one another, lie against the base wall 44, and lower marginal regions 46 of the wall surfaces 45 adjoining the flanges 36 touch the wings 43. The front section 28 is therefore reinforced on almost its entire cross-section by a material layer of the wall parts 29. As the doubling of material extends respectively on both sides of a curvature zone 47 running between the wings 43 and the base wall 44, and the front section 28 is connected with the wall parts 29, 30 by weld points 48 on both sides of the curvature 47, the longitudinal beam is efficiently reinforced especially in its lower region also in the case of a small wall thickness of the sections 25, 28 and wall parts 29, 30, and therefore is able to be highly stressed despite a small cross-section.

The structure of the longitudinal beams, explained above, of shaped parts 9, 25, 26, 27, 28, 29, 30 facilitates the manufacture of different body types, which differ in the length both of the passenger compartment 5 and also of a trunk 8 adjoining behind the latter (see FIG. 1). As the roll-formed rear sections 26, 27 are available as endless material, different lengths of the trunk or respectively different values of the rear overhang d1 (see FIG. 1) can be realized in a simple manner, in which the sections 26, 27 are cut off from the endless string in the respectively required length. However, in order to also be able to vary the wheelbase d2 in a compatible manner to an altered rear overhang d1 and—via the position of the heel plate 6—to vary the length of the passenger compartment 5 and to maintain balanced proportions of the body, different models of the front sections 25, 28 and wall parts 29, 30 are provided here.

FIG. 6 shows respectively superimposed on one another two different models of the front section 28 and of the wall parts 29, 30 of the assembly 24, wherein the longer model is respectively designated with dashed lines. The two models of the front section 28 differ only in the length of the connection 15 for the central longitudinal beam section 9; this is enlarged by I in the longer model. Both models of the front section 28 can therefore be manufactured at a favorable cost, in which blanks of respectively model-specifically different length are deep-drawn at least partially with forming tools which are comprehensively identical over the models.

In the case of the wall parts 29, 30, the lower flanges 36 are respectively of identical shape in both the models which are shown, and extend only in the longer model further forward by the distance I, in order to continue the reinforcement by the doubling of material up to the front connection 15. The upper flanges 35 and the cutout 31 receiving the roll-formed profile 13 are displaced forward by a distance s in the longer model, whilst maintaining their shape, this distance being able to be selected to be shorter, equal to or longer than the length difference 1. The lower flanges 36 on the various models of wall parts 29, 30 are shaped and cut with an identical set of tools, independently of the values of s and 1; specific tools only come into use on shaping of the upper flanges 35, according to the value of s, as will be explained in further detail with the aid of FIG. 9.

By the values of 1 and s being established independently of one another, the position of the heel plate 6 and the wheelbase d2 can be varied respectively independently of one another; in the longer of the two models shown in FIG. 6, the wheelbase d2 is greater by 1 than in the shorter model, whilst the distance of the heel plate 6 from the rear wheel axis 3 is increased by s, and the length of the passenger compartment 5 is consequently increased by 1-s.

According to the various models of the front section 28 and of the wall parts 29, 30 of the assembly 24, different models of the front section 25 of the upper shell 23 must also be provided. Two such models of the front section are illustrated in FIG. 8 in superposition. Here, also, it can easily be seen that two sets of deep-drawing tools are sufficient, in order to form any desired number of models of the front section 25 of different length, namely a set for forming a flange 49 complementary to the upper flange 35 of the inner wall part 29 and the surface lying against the flange 35 of the outer wall part 30, and a set for forming a flange 50 on an edge of the front section 25 lying opposite the flange 49, which is provided for fastening to a wheel arch.

FIG. 9 a-9 d show, in the example of the wall part 29, steps of a manufacturing process which enables an efficient and economically priced manufacture of variants of the wall part. Although the process is only explained with respect to this one wall part, its transfer to the wall part 30 or to the front section 25 of the upper shell 23 will be readily appreciated by one of ordinary skill in the art.

In order to manufacture the wall part 29 in different lengths, sheet metal coils with different widths a, b can be provided, in order to separate from these respectively blanks 51 a, 51 b. These blanks 51 a, 51 b are initially flat, as shown in FIG. 9 a by means of a section illustration between the top views of the two blanks 51 a, 51 b.

The two blanks 51 a, 51 b are respectively processed in succession in a deep-drawing device. For this, the blanks are firstly fixed between two clamping jaws 52 of the deep-drawing device. Regions 53 of the blanks 51 a, 51 b clamped between the clamping jaws 52 are highlighted in FIG. 9 b by hatching. As identical clamping jaws 52 are used for both blanks 51 a, 51 b, the clamped regions 53 on both blanks 51 a, 51 b are congruent. The length b of the blank 51 b corresponds to the length of the clamping jaws; when the shorter blank 51 a is processed, a portion 54 of the clamping jaws 52 remains respectively uncovered.

As shown in FIG. 9 c, a strip 55 extends beneath the clamped region 53 on both blanks 51 a, 51 b, which strip on the finished wall part 29 is to be rounded towards the left in cross-section, and adjoining the strip 55 there is a region 56, which on the finished wall part will form the lower flange 36. As the shape of the strip 55 and the course of the flange 36 is identical in both models of the wall part 29, as shown in FIG. 6, a punch 57, on which the strip 55 is formed, can be a fixed component of the left-hand clamping jaw 52. A die 58, which cooperates with the punch 57, in order to bend the strip 55 and form the region 56 to the flange 36, is movable on the right-hand clamping jaw 52.

In FIG. 9 c in addition a region 59 a, 59 b above the clamped region 53 is highlighted on the blanks, the shape of which region is different in the two blanks 51 a, 51 b. In order to form the upper flange 35 respectively along the edge of this region 59 a, 59 b, different models of punch 60 and die 61 are necessary for the two blanks 51 a, 51 b. These are therefore mounted interchangeably on the clamping jaws 52. The deep-drawing can take place simultaneously or successively above and beneath the clamped region 53.

FIG. 9 d shows on an enlarged scale compared with FIG. 9 a-c a cross-section through the clamping jaws, punches and dies and the blank 51 a or 51 b formed between them after the pushing together of the punches 57, 60 and dies 58, 61. The blank now only still has to be trimmed on the edges by blades 62 which are movable on the dies 58, 61, in order to complete the wall part 29.

When the two deep-drawing steps above or respectively beneath the clamped region are carried out in succession, it is also possible to distribute them to different deep-drawing devices and thus for example to form in a first device the lower flange 36 which is identical for all models of the wall part 29, and to subsequently distribute the blanks 51 a, 51 b to respectively different deep-drawing devices, in order to form the model-specific upper flange 35 therein.

A process with successive deep-drawing steps is also shown in FIG. 10 a-d. FIG. 10 a shows two blanks placed one over another, a short blank 51 a traced out in dashed lines, and a long blank 51 b traced out in solid lines. In order to carry out a first deep-drawing step which is uniform for both blanks, in which the lower flange 36 is formed, a deep-drawing tool, not shown in the figure, is placed taking reference from a shared reference point of both blanks 51 a, 51 b, for example an edge 63, and is actuated in order to obtain the semi-finished parts, shown in FIG. 10 b, with a shaped lower flange 36. Subsequently, a second deep-drawing tool is placed with reference to an opposite edge 64 a, 64 b of the blanks 51 a, 51 b and is actuated in order to form the upper flange 35. FIG. 10 c shows the wall part 29 obtained in this way from the long blank 51 b, FIG. 10 d the one obtained from the short blank 51 a, 51 b. The shape of the flanges 35, 36 is indeed the same in the two wall parts, however the two flanges 35, 36 are offset with respect to one another respectively according to the difference in length between the two blanks 51 a, 51 b.

In the illustration of FIGS. 1 and 2, the transverse beams 10, 11 are composed respectively in several parts from roll-formed profiles 16, 17 and extensions 18, 19. With a modification of the method according to the present disclosure, transverse beam components can be manufactured, which extend in a single piece between the longitudinal beams 1. For this, firstly again a flat sheet metal blank is provided. The length of the blanks can vary according to the desired width of the vehicle body. In the illustration of FIG. 11 b, at both head ends of such a blank 65, contours 66 corresponding to the extensions 18 with a horizontal flange 67 and section 68 adjoining thereon with a hat-shaped cross-section are deep-drawn by means of a punch 69 and a die 70. A central region 71 of the blank is still flat; as the contours 66 have respectively a fixed length predetermined by the dimensions of punch 69 and die 70, the length of the central region 71 varies according to the length of the original blank 65. In a method step shown in FIG. 11 b, the central region 71 is roll-formed, in order to give it the same hat-shaped cross-section as in the sections 68.

While at least one exemplary embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment is only an example, and are not intended to limit the scope, applicability, or configuration of the present disclosure in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope of the present disclosure as set forth in the appended claims and their legal equivalents. 

1-11. (canceled)
 12. A method for the manufacture of motor vehicle body parts comprising (a) selecting one of a first deep-drawing contour and a second deep-drawing contour for a body part; (b) providing blanks of flat material; (c) deep-drawing of the blanks on a first forming tool when the first deep-drawing contour is selected to form the body part; and (d) deep-drawing of the blanks on a second forming tool when the second deep-drawings contour is selected to form the body part.
 13. The method according to claim 12, further comprising selecting the first forming tool and the second forming tool from a set of several forming tools.
 14. The method according to claim 13, wherein blanks are provided with different values of a dimension, and selecting the first forming tool and the second forming tool takes place by means of the value of the dimension.
 15. The method according to claim 12, further comprising placing the first forming tool for carrying out (c) relative to a first reference point of the blank, and placing of the second forming tool for carrying out (d) relative to a second reference point of the blank.
 16. The method according to claim 15, wherein carrying out (b) blanks are provided with different values of a dimension, and the distance between the reference points is different according to the value of the dimension.
 17. The method according to claim 14, wherein the dimension is a longitudinal dimension of the blank.
 18. The method according to claim 12, wherein the first and second deep-drawing contours are formed on marginal regions of each flat material blank which are separate from one another.
 19. The method according to claim 12, wherein the first and second deep-drawing contours are formed on opposite longitudinal edges of each flat material blank.
 20. The method according to claim 12, wherein the first and second deep-drawing contours are formed at opposite head ends of each flat material blank.
 21. The method according to claim 20 further comprising roll-forming a central section of each flat material blank connecting the head ends.
 22. The method according to claim 12 wherein the body parts comprise parts of body substructures including beams of motor vehicle bodies for different vehicle models. 